The {% url %} Tag in Django

# urls.py
urlpatterns = [
    path('tasks/', views.task_list, name='task-list'),
    path('tasks/<int:pk>/', views.task_detail, name='task-detail'),
    path('tasks/new/', views.task_create, name='task-create'),
]

<!-- Simple URL -->
<a href="{% url 'task-list' %}">All tasks</a>
<!-- Result: /tasks/ -->

<!-- URL with parameter -->
<a href="{% url 'task-detail' pk=task.pk %}">{{ task.title }}</a>
<!-- Result: /tasks/42/ -->

<!-- Positional argument -->
<a href="{% url 'task-detail' task.pk %}">{{ task.title }}</a>

<a href="{% url 'tasks:list' %}">List</a>
<a href="{% url 'tasks:detail' pk=task.pk %}">Details</a>

{% url 'task-detail' pk=task.pk as task_url %}
<a href="{{ task_url }}">Link</a>

<!-- Useful for conditional rendering -->
{% url 'task-edit' pk=task.pk as edit_url %}
{% if edit_url %}
  <a href="{{ edit_url }}">Edit</a>
{% endif %}

# url: /courses/<course_slug>/lessons/<lesson_pk>/
path('<slug:course_slug>/lessons/<int:lesson_pk>/', views.lesson_detail, name='lesson-detail'),

{% url 'lesson-detail' course_slug=course.slug lesson_pk=lesson.pk %}

<!-- Bad: hardcoded path -->
<a href="/tasks/{{ task.pk }}/">Task</a>

<!-- Good: when the URL changes in urls.py, templates update automatically -->
<a href="{% url 'task-detail' pk=task.pk %}">Task</a>